Fundamental and Technological Aspects of Finishing Balls of Advanced Ceramics, Glasses, and Silicon Using Magnetic Field Assisted Polishing

该项目是关于使用磁悬浮抛光技术对先进陶瓷、玻璃和半导体材料的球体进行抛光。传统的先进陶瓷和玻璃的研磨、抛光、研磨加工通常会产生一些缺陷，包括大划痕、由于颗粒移位而形成的凹坑、玻璃中玻璃相的粘性流动以及表面和亚表面微裂纹。这些缺陷会影响这些材料的性能和性能，传统上会通过后续的钻石抛光来消除。为了解决这一难题，开发了一种名为磁浮抛光的“温和”抛光技术(在NSF支持的最近完成的一项调查中)，而不需要使用钻石磨料。在氮化硅抛光球上实现了4nmRa和40nmRmax量级的抛光，球度在0.25微米范围内，总抛光时间约为20h。对氮化硅抛光过程中涉及的机械和化学-机械作用有了更好的理解。在这个项目中，研究人员打算将这项工作推广到其他先进陶瓷(每批不同大小和数量的球)、各种玻璃和硅。先进的陶瓷材料，如Si3N4、SiC、Zr02和Al_2O_3，正越来越多地被考虑用于结构应用，其中Si3N4尤其被选作混合球和滚子轴承的应用。同样，各种类型的玻璃被用于光学应用，例如透镜，最近正在考虑将球形硅球用于微电子应用(而不是硅晶片)。这项研究将是第一次用磁浮抛光来抛光硅球(而不是晶片)。因此，拟议的精加工技术有望解决结构、光学和电子应用，这些应用可能对各种先进技术应用的球的制造产生重大影响。

This project is on the finishing of balls of advanced ceramics, glasses, and semiconductor material using the magnetic float polishing technology. Conventional finishing of advanced ceramics and glasses by grinding, polishing, lapping generally leads to several defects including large scratches, formation of pits due to the dislodgment of grains, viscous flow of the glassy phase in the case of glass, and surface and subsurface microcracks. These defects affect the properties and performance of these materials and are traditionally removed by subsequent diamond polishing. To address this difficult problem, a "gentle" finishing technology, called the magnetic float polishing was developed (in a recently completed investigation supported by NSF) without the need to use diamond abrasives. Surface finish on the order of 4 nm Ra and 40 nm Rmax with sphericity in the range of 0.25 micrometers were accomplished on Si3N4 balls with a total polishing time of ~ 20 hours. A better understanding of the mechanical and chemo-mechanical actions involved in the polishing of Si3N4 balls has resulted. In this project, the investigators intend to generalize this work to cover other advanced ceramics (balls of different size and number per batch), various glasses, and silicon. Advanced ceramics, such as Si3N4, SiC, Zr02, and Al2O3 are increasing being considered for structural applications of which Si3N4, in specific, is chosen for hybrid ball and roller bearing applications. Similarly, various types of glasses are used for optical applications, such as lenses and recently spherical silicon balls are being considered for micro-electronic applications (instead of silicon wafers). This research would be the first of its kind on the finishing of silicon balls (instead of wafers) by magnetic float polishing. Thus, the finishing technology proposed is expected to address structural, optical, and electronic applications that can have a significant impact on the manufacture of balls for various advanced technology applications.